This invention relates to a preservative composition useful for stabilizing and preserving the biochemical characteristics of urine to enable testing and analysis thereof. More particularly this invention provides a preservative which may be added to human urine containing bacterial contamination resultant from infection to stabilize both pH and uric acid content of the urine for subsequent analysis.
Analysis of urine is often necessary in the diagnosis and treatment of urological disorders or infections. In such analyses, pH and uric acid content of the urine are frequently sought to be determined. However, if urine is permitted to stand at room temperature for a prolonged period of hours, the pH of the sample will frequently change as a result of the growth of bacterial infection present. Furthermore, uric acid concentration of the sample frequently changes upon standing as a result of a biochemical mechanism not completely understood.
It has been suggested that stabilization of uric acid in the sample might be effected by creating and maintaining an alkaline environment for the sample. However, it has been found that many standard alkaline materials either are not bactericidal or affect pH adversely. Stabilization of urine for analysis of minerals such as calcium, magnesium, phosphorus, sodium and potassium or for analysis of ammonia is accomplished using sulfamic acid. However, sulfamic acid does not stabilize pH or uric acid content.
Known germicidal compositions such as benzyl (dodecyl carbamylmethyl) dimethyl ammonium chloride have also been found ineffective when employed for this purpose.